/* CoralCube | Massively Multiplayer Online Role-Playing Game(MMORPG) Emulator.
|* 
|* Copyright (C) 2005-2010 MaNGOS <http://getmangos.com/>
|*               2008-2010 TrinityCore <http://www.trinitycore.org/>
|*               2008-2010 CoralCube <http://www.CoralCube.com/>
|*
|* This program is free software. You can redistribute it and/or modify it under the terms of 
|* the GNU General Public License as published by the Free Software Foundation, either 
|* version 2 of the License.
|*
|* This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY, 
|* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
|* See the GNU General Public License for more details.
|*
|* You should have received a copy of the GNU General Public License along with this program. 
|* If not, see <http://www.gnu.org/licenses/>.
|*/

#ifndef _WORLDSOCKET_H
#define _WORLDSOCKET_H

#include <ace/Basic_Types.h>
#include <ace/Synch_Traits.h>
#include <ace/Svc_Handler.h>
#include <ace/SOCK_Stream.h>
#include <ace/SOCK_Acceptor.h>
#include <ace/Acceptor.h>
#include <ace/Thread_Mutex.h>
#include <ace/Guard_T.h>
#include <ace/Unbounded_Queue.h>
#include <ace/Message_Block.h>

#if !defined (ACE_LACKS_PRAGMA_ONCE)
#pragma once
#endif /* ACE_LACKS_PRAGMA_ONCE */

#include "Common.h"
#include "AuthCrypt.h"

class ACE_Message_Block;
class WorldPacket;
class WorldSession;

/// Handler that can communicate over stream sockets.
typedef ACE_Svc_Handler<ACE_SOCK_STREAM, ACE_NULL_SYNCH> WorldHandler;

/**
* WorldSocket.
*
* This class is responsible for the communication with
* remote clients.
* Most methods return -1 on failure.
* The class uses reference counting.
*
* For output the class uses one buffer (64K usually) and
* a queue where it stores packet if there is no place on
* the queue. The reason this is done, is because the server
* does really a lot of small-size writes to it, and it doesn't
* scale well to allocate memory for every. When something is
* written to the output buffer the socket is not immediately
* activated for output (again for the same reason), there
* is 10ms celling (thats why there is Update() method).
* This concept is similar to TCP_CORK, but TCP_CORK
* uses 200ms celling. As result overhead generated by
* sending packets from "producer" threads is minimal,
* and doing a lot of writes with small size is tolerated.
*
* The calls to Update() method are managed by WorldSocketMgr
* and ReactorRunnable.
*
* For input ,the class uses one 1024 bytes buffer on stack
* to which it does recv() calls. And then received data is
* distributed where its needed. 1024 matches pretty well the
* traffic generated by client for now.
*
* The input/output do speculative reads/writes (AKA it tryes
* to read all data available in the kernel buffer or tryes to
* write everything available in userspace buffer),
* which is ok for using with Level and Edge Triggered IO
* notification.
*
*/
class WorldSocket : protected WorldHandler
{
public:
    /// Declare some friends
    friend class ACE_Acceptor< WorldSocket, ACE_SOCK_ACCEPTOR >;
    friend class WorldSocketMgr;
    friend class ReactorRunnable;

    /// Declare the acceptor for this class
    typedef ACE_Acceptor< WorldSocket, ACE_SOCK_ACCEPTOR > Acceptor;

    /// Mutex type used for various synchronizations.
    typedef ACE_Thread_Mutex LockType;
    typedef ACE_Guard<LockType> GuardType;

    /// Check if socket is closed.
    bool IsClosed (void) const;

    /// Close the socket.
    void CloseSocket (void);

    /// Get address of connected peer.
    const std::string& GetRemoteAddress (void) const;

    /// Send A packet on the socket, this function is reentrant.
    /// @param pct packet to send
    /// @return -1 of failure
    int SendPacket (const WorldPacket& pct);

    /// Add reference to this object.
    long AddReference (void);

    /// Remove reference to this object.
    long RemoveReference (void);

protected:
    /// things called by ACE FrameWork.
    WorldSocket (void);
    virtual ~WorldSocket (void);

    /// Called on open ,the void* is the acceptor.
    virtual int open (void *);

    /// Called on failures inside of the acceptor, don't call from your code.
    virtual int close (u_long);

    /// Called when we can read from the socket.
    virtual int handle_input (ACE_HANDLE = ACE_INVALID_HANDLE);

    /// Called when the socket can write.
    virtual int handle_output (ACE_HANDLE = ACE_INVALID_HANDLE);

    /// Called when connection is closed or error happens.
    virtual int handle_close (ACE_HANDLE = ACE_INVALID_HANDLE,
        ACE_Reactor_Mask = ACE_Event_Handler::ALL_EVENTS_MASK);

    /// Called by WorldSocketMgr/ReactorRunnable.
    int Update (void);

private:
    /// Helper functions for processing incoming data.
    int handle_input_header (void);
    int handle_input_payload (void);
    int handle_input_missing_data (void);

    /// Help functions to mark/unmark the socket for output.
    /// @param g the guard is for m_OutBufferLock, the function will release it
    int cancel_wakeup_output (GuardType& g);
    int schedule_wakeup_output (GuardType& g);

    /// Drain the queue if its not empty.
    int handle_output_queue (GuardType& g);

    /// process one incoming packet.
    /// @param new_pct received packet ,note that you need to delete it.
    int ProcessIncoming (WorldPacket* new_pct);

    /// Called by ProcessIncoming() on CMSG_AUTH_SESSION.
    int HandleAuthSession (WorldPacket& recvPacket);

    /// Called by ProcessIncoming() on CMSG_PING.
    int HandlePing (WorldPacket& recvPacket);

private:
    /// Time in which the last ping was received
    ACE_Time_Value m_LastPingTime;

    /// Keep track of over-speed pings ,to prevent ping flood.
    uint32 m_OverSpeedPings;

    /// Address of the remote peer
    std::string m_Address;

    /// Class used for managing encryption of the headers
    AuthCrypt m_Crypt;

    /// Mutex lock to protect m_Session
    LockType m_SessionLock;

    /// Session to which received packets are routed
    WorldSession* m_Session;

    /// here are stored the fragments of the received data
    WorldPacket* m_RecvWPct;

    /// This block actually refers to m_RecvWPct contents,
    /// which allows easy and safe writing to it.
    /// It wont free memory when its deleted. m_RecvWPct takes care of freeing.
    ACE_Message_Block m_RecvPct;

    /// Fragment of the received header.
    ACE_Message_Block m_Header;

    /// Mutex for protecting output related data.
    LockType m_OutBufferLock;

    /// Buffer used for writing output.
    ACE_Message_Block *m_OutBuffer;

    /// Size of the m_OutBuffer.
    size_t m_OutBufferSize;

    /// True if the socket is registered with the reactor for output
    bool m_OutActive;

    uint32 m_Seed;
};

#endif  /* _WORLDSOCKET_H */
